Functional Analysis Of Two Csps And Effects Of Four Compounds On Their Expression,Growth And Development Of Bombyx Mori

Sericulture is a conventional superiority industry in China With a history of more than five thousand years.With the development of society and economy,the sericulture industry is in urgent need of transformation and upgrading,and the rearing silkworm with artificial diet is the part and parcel of the modernization in sericulture industry.However,there still exist great differences in growth and development,resistance,cocoon quality and silk quality between silkworm reared with artificial diet and mulberry leaf.What caused these differences remains to be explored.In this paper,based on the midgut transcriptome and proteome database of mulberry leaf rearing and feed rearing silkworm,CSP5 and CSP8 with large differences were excavated.We analyzed the two BmCSPs with Bioinformatics,spatio-temporal expressiona characteristics,starvation treatment,effect of mixed oil adding on their expression,and molecular docking.Based on the analysis and results,we identified four stable compounds,and instigated the effects of these four compounds on their expression,growth and cocoon quality of silkworm reared with semi-synthetic diet,in order to indicated their functions in artificial diet,and provide theoretical support for the optimization of diet formula.The results are as follows:1.Female silkworm were reared with artificial diet and mulberry until the 5^thinstar 4^thday,and their midgut transcriptome and proteome databases were excavated.The BmCSP5and BmCSP8 expression levels in the midgut of B.mori reared with artificial diet were significantly higher than those with mulberry leaf,and the differences were more than twice.The results of q RT-PCR were consistent with those results oftranscriptome and proteome,and the difference was more than 1.6 times.2.Bioinformatics analysis of BmCSP5 protein and BmCSP8 protein showed that they were small molecular proteins without transmembrane region,and both contained some hydrophobic amino acids,and highly conserved.3.q RT-PCR was utilized to detect the expression characteristics of BmCSP5 and BmCSP8 in the larval stage of B.mori,and the relative expression of BmCSP5 and BmCSP8 in the midgut of B.mori treated with starvation and mixed oil.It confirmed that BmCSP5 and BmCSP8 were expressed in all tissues of the 5^thinstar larvae of B.mori.The relative expression of BmCSP5 gradually decreased with the development of instar,and the relative expression of BmCSP8 was the highest in the 5^thinstar larvae.Their relative expression in the midgut of 12 h starvation was higher than that of other starvation treatments.The relative expression level was highest in the midgut of silkworm fed with 2.5%mixed oil.4.Auto Dock Tools software was employed for molecular docking of BmCSP5 protein and BmCSP8 protein with oleic acid,linoleic acid,β-sitosterol and stigmasterol,respectively.The results showed that BmCSP5 protein had strong combining capacity with oleic acid,stigmasterol andβ-sitosterol,and BmCSP8 protein with oleic acid,linoleic acid and stigmasterol.5.The relative expression levels of BmCSP5 and BmCSP8 in the midgut of silkworm fed semi-synthetic diets supplemented with 1.35%oleic acid,0.12%stigmasterol and 0.15%β-sitosterol were detected.The highest expression of BmCSP8 was observed in the midgut of silkworm fed semi-synthetic diets supplemented with 1.35%oleic acid,5.2%linoleic acid and0.12%stigmasterol,respectively.Therefore,BmCSP5 and BmCSP8 may assume the function of carrier in the midgut of B.mori.The investigation on the growth and development of B.mori and cocoon quality showed that the body weight of B.mori in the treatment group with1.35%oleic acid,0.15%β-sitosterol and 0.12%stigmasterol was higher than that in the control group without addition,and the cocoon quality,cocooning rate and pupal life rate also showed the same trend.The body weight of silkworms with 5.2%linoleic acid was significantly lower than that of the control group,and all of them were non-cococoon silkworms.